OBD issue?

I scanned it before, and it was fine. But now I am trying to find out why the battery drains if I leave it parked 3 days or so, especially if I use the fob to lock it. Battery has been replaced, but not an agm battery. I checked all the fuses under the hood, in the trunk. I cant find any fuses inside the car on either side. This is a 335 so they are maybe different, nothing behind the passenger kick panel. I took down the obd connector and it looks fine. Where should power be going to on the obd? And I want to apply power to it to see if it starts to work using the probe tester will that work? Only obd I saw marked based on online checking is one under the hood. In the trunk the fuses are under the cargo carpet towards the inside.